Bag opening device

ABSTRACT

A bag opening device comprising a pair of suction heads adapted to engage a portion of a bag from one side thereof and to twist the bag to open the mouth thereof when the heads are moved in opposite directions. The suction heads are movably mounted on the ends of a pair of suction arms and are positioned to engage a cam member to effect the opposite movement of the heads in response to predetermined movement of the suction arms. The suction heads may be mounted on the suction arms for rotatable or reciprocatory movement relation thereto.

United States Patent Kaneko et al.

[451 Dec. 19, 1972 [54] BAG OPENING DEVICE [72] Inventors: Keiii Kaneko; Kitimaru Shoji; Minoru Mukai, all of Minami Ashigara, Kanagawa, Japan 73 Assignee: Fuji Photo Film Ltd.,

Kanagawa, Japan [22] Filed: June 30, 1971 [21] Appl. No.: 158,323

[] Foreign Application Priority Data June 30, 1970 Japan ..45/57054 [52] U.S. Cl ..53/386, 53/188 [51 Int. Cl. ..Bb 43/28 [58] Field of Search ..53/386, 188, 190

[56] References Cited UNITED STATES PATENTS 3,501,893 3/1970 Peterson ..53/l

3,566,578 3/l97l Thorne et al. ..53/ X Primary Examiner-Travis S. McGehee Attarney-Richard C. Sughrue et al.

[5 7 ABSTRACT A bag opening device comprising a pair of suction heads adapted to engage a portion of a bag from one side thereof and to twist the bag to open the mouth thereof when the heads are moved in opposite directions. The suction heads are movably mounted on the ends of a pair of suction arms and are positioned to engage a cam member to effect the opposite movement of the heads in response to predetermined movement of the suction arms. The suction heads may be mounted on the suction arms for rotatable or reciprocatory movement relation thereto.

. 10 Claims, 3 Drawing Figures PATENTED 02c 19 I972 INVE S KEIJI KANE MINORU MUKAI KITIMALU SYOJI ATTORNEYS BAG OPENING DEVICE BACKGROUND OF THE INVENTION The present invention relates to a device for automatically opening the mouth of a bag, and in particular to a device for opening the mouth of a flexible bag formed of a material such as polyethylene employed in an automatic packaging machine. I

Heretofore in the packaging process, including a step of wrapping articles in flexible bags formed of materials such as polyethylene, the automatization of the process of opening the mouth of the bag has been slow and complicated, which results in low efficiency in the entire process of packaging.

SUMMARY OF THE INVENTION In light of the above conventional disposition, it is a primary object of the present invention to provide an automatic bag opening device which opens automatically and certainly the mouth of a flexible bag.

Another object of the present invention is to provide an automatic bag opening device which swiftly opens the mouth of a flexible bag.

BRIEF DESCRIPTION OF THE DRAWING Other objects and features of the present invention will be made apparent from the following description of the present invention taken in conjunction with the accompanying drawing in which:

FIG. 1 is a perspective view'showing the main portion of the device constructed in accordance with the present invention;

FIG. 2 is a front view showing the main portion of the device constructed in accordance with another embodiment of the invention; and

FIG. 3 is a side view of the device shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A brief summary or explanation of the principles of the present invention will be helpful in order to fully understand the invention.

It is often experienced that a flexible bag formed of a material such as polyethylene can be easily opened by holding the bag withfingers on the opposite edge portions thereof and twisting the bag by slipping the fingers I inwardly. Particularly in the case where the bag mouth is tightly closed by adhesion or the like, this is one of the effective ways in which to open the mouth. The device in accordance with the present invention automatically opens the mouth of the flexible bag utilizing the above principle.

Referring to the drawing, FIG. 1 illustrates an embodiment of the device of the invention wherein the reference numeral 1 shows a flexible bag to be opened. The bag 1 shown in FIG. 1 has a mouth. A pair of suction pipes 2 are fixed to a hollow shaft 3 connected to a vacuum pump and rotatable about its axis. A suction head 20 is rotatably mounted on the end of each suction pipe 2. In further detail, the suction head 20 is secured to a hollow cylindrical member 21 serving as a suction head holder which, in turn, is rotatably mounted on the suction pipe 2 with the intervention of tension spring 51. The tension spring 51 urges the suction head holder 51 in one direction around the suction pipe 2 so as to normally urge the holder 21 to the normal position determined by a stopper pin 52 fixed on the pipe 2.

Between the suction pipes 2, a cam member 4 is provided. The cam member 4'is fixed to a support 41 and the shaft 3 is rotatably supported thereby. On the suction head holders 21 are disposed roller supporting members 22 which hold rollers 53 to follow the cam surface of the cam member 4. When the suction pipes 2 are rotated together with the hollow shaft 3, the cam follower rollers 53 ride on the cam surface and the supporting members 22 are moved to rotate the suction head holders 21. Thus, the suction heads 20 are rotated about the axis of the suction pipes 2. That is, when the hollow shaft 3 is rotated in the direction of the arrow A, the suction head holders 21 are rotated in the direction of arrow B.

The suction pipes 2 are rotated around the axis of the hollow shaft 3 and, during such rotation, the suction pipes 2 remove one bag from the bag accumulation in a hopper (not shown) by suction and move the bag downwardly to a bag receiving bracket (not shown). While the pipes 2 move the bag downwardly, the suction head holders 21 are rotated around the pipes 2 by the cam member 4 and, accordingly, the suction heads 20 are rotated to twist the bag mouth and open it. The bag with the mouth thus opened may be supplied to a pin (not shown) to receive the bag or may be brought to a bracket (not shown) to receive it. The suction pipes 2 repeat the above described operation by repeated rotation thereof in the manner described above.

In FIGS. 2 and 3, another embodiment of the device of the present invention is shown, in which the suction heads are reciprocated laterally instead of being rotated. Namely, by the inward lateral movement of the suction heads, the mouth of the flexible bag is opened based on the same principle as utilized above.

In the embodiment of FIGS. 2 and 3, a guide member 34 having a groove 33 is fixed to the end of the suction pipe 2'. The groove 33 extends in parallel relation to the axial direction of the shaft 3' and receives a rail 35 on a slide member 36 so that the slide member 36 may be moved in the direction parallel to the shaft 3'. The slide member 36 is urged outwardly by a tension spring 37 connected between the slide member 36 and the suction pipe 2. At the outer end of the slide member 36 is provided a roller 32 positioned to follow a cam member 5 disposed at a fixed position to move the slide member 36 inwardly against the tension of the spring 37. On the bottom of the slide member 36 is provided a suction head 30 sealingly connected to a vacuum pump (not shown).

In operation of the second embodiment of the invention, the suction pipes 2' are rotated with the shaft 3 and, during the rotation thereof, the slide member 36 is moved inwardly by the engagement of the roller 32 with the cam member 5. Therefore, the suction heads 30 are moved inwardly and serve to twist the mouth of the flexible bag 1 to open it. Other than the structure described above, the construction of the device in accordance with the second embodiment of the invention is substantially the same as that of the first embodiment.

What is claimed is:

1. A bag opening device comprising a pair of suction heads adapted to engage a portion of a bag from one side thereof, and means for moving said suction headsrelative to each other when-they are in suction engagement with said bag so as to twist open the mouth of the bag.

2. A bag opening device as defined in claim 1 wherein said suction heads are rotatable in opposite directions when they are in suction engagement with the bag.

-3. A bag opening device as defined in claim 2, further comprising a pair of rotatable suction arms adapted to convey the bags from one position to another, and said suction heads are rotatably mounted on the outer end of said suction arms for rotation about the longitudinal axis of said arms.

4. A bag opening device as defined in claim 3 wherein a holder is rotatably mounted on the suction arm, and said heads are fixed to said holder.

5. A bag opening device as defined in claim 4 wherein said holder is provided with a cam follower, and a cam member is fixed at a predetermined position and is engageable by said follower when said arms are rotated in a predetermined direction.

6. A bag opening device as defined in claim 5 wherein said cam member is positioned between said suction arms.

7. A bag opening device as defined in claim 1 wherein said suction heads are movable in opposite directions while they are in suction engagement with the bag.

8. A bag opening device as defined in claim 7, further comprising a pair of suction pipes, said suction heads being movably mounted on the ends of said suction pipes, spring means for urging said suction heads in a first direction relative to said pipes, and the suction heads being engageable with a cam member to move them in a direction opposite to said first direction.

9. A bag opening device as defined in claim 8 wherein said suction heads are slidably mounted for reciprocatory movement on said suction pipes.

10. A bag opening device as defined in claim. 9 wherein said suction heads are fixed on slidable members that are slidably mounted on said suction pipes for movement toward each other. 

1. A bag opening device comprising a pair of suction heads adapted to engage a portion of a bag from one side thereof, and means for moving said suction heads relative to each other when they are in suction engagement with said bag so as to twist open the mouth of the bag.
 2. A bag opening device as defined in claim 1 wherein said suction heads are rotatable in opposite directions when they are in suction engagement with the bag.
 3. A bag opening device as defined in claim 2, further comprising a pair of rotatable suction arms adapted to convey the bags from one position to another, and said suction heads are rotatably mounted on the outer end of said suction arms for rotation about the longitudinal axis of said arms.
 4. A bag opening device as defined in claim 3 wherein a holder is rotatably mounted on the suction arm, and said heads are fixed to said holder.
 5. A bag opening device as defined in claim 4 wherein said holder is provided with a cam follower, and a cam member is fixed at a predetermined position and is engageable by said follower when said arms are rotated in a predetermined direction.
 6. A bag opening device as defined in claim 5 wherein said cam member is positioned between said suction arms.
 7. A bag opening device as defined in claim 1 wherein said suction heads are movable in opposite directions while they are in suction engagement with the bag.
 8. A bag opening device as defined in claim 7, further comprising a pair of suction pipes, said suction heads being movably mounted on the ends of said suction pipes, spring means for urging said suction heads in a first direction relative to said pipes, and the suction heads being engageable with a cam member to move them in a direction opposite to said first direction.
 9. A bag opening device as defined in claim 8 wherein said suction heads are slidably mounted for reciprocatory movement on said suction pipes.
 10. A bag opening device as defined in claim 9 wherein said suction heads are fixed on slidable members that are slidably mounted on said suction pipes for movement toward each other. 